Add specs for GraphqlHelpers.graphql_mutation

spec/support_specs/helpers/graphql_helpers_spec.rb

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe GraphqlHelpers do
+  include GraphqlHelpers
+
+  describe '.graphql_mutation' do
+    shared_examples 'correct mutation definition' do
+      it 'returns correct mutation definition' do
+        query = <<~MUTATION
+          mutation($updateAlertStatusInput: UpdateAlertStatusInput!) {
+            updateAlertStatus(input: $updateAlertStatusInput) {
+              clientMutationId
+            }
+          }
+        MUTATION
+        variables = %q({"updateAlertStatusInput":{"projectPath":"test/project"}})
+
+        is_expected.to eq(GraphqlHelpers::MutationDefinition.new(query, variables))
+      end
+    end
+
+    context 'when fields argument is passed' do
+      subject do
+        graphql_mutation(:update_alert_status, { project_path: 'test/project' }, 'clientMutationId')
+      end
+
+      it_behaves_like 'correct mutation definition'
+    end
+
+    context 'when block is passed' do
+      subject do
+        graphql_mutation(:update_alert_status, { project_path: 'test/project' }) do
+          'clientMutationId'
+        end
+      end
+
+      it_behaves_like 'correct mutation definition'
+    end
+
+    context 'when both fields and a block are passed' do
+      subject do
+        graphql_mutation(:mutation_name, { variable_name: 'variable/value' }, 'fieldName') do
+          'fieldName'
+        end
+      end
+
+      it 'raises an ArgumentError' do
+        expect { subject }.to raise_error(
+          ArgumentError,
+          'Please pass either `fields` parameter or a block to `#graphql_mutation`, but not both.'
+        )
+      end
+    end
+  end
+end